Such fluid bag system for fractionating a fluid usually consists of a first collecting bag used for collecting the fluid and one or more sub-bags used for fractionating the fluid into separated fluid products. Plastic tubing couples said bags together to form a so-called closed multiple fluid bag system. Typical system comprises four or five bags in fluid communication such that once a fluid is introduced into the system, the fluid or its components may be moved from one bag to another by external manipulation of valves, and the like, thereby avoiding contamination. Depending on the configuration, the fluid bag system may also include a filter, downstream the fluid bag.
In a typical multiple fluid bag system application, a fluid is collected into a first bag and all connected bags, which are usually empty, are placed in a centrifuge. The bag contents are then centrifuged to separate the fluid into its components (see FIG. 1A). By manipulating a valve, which is typically a frangible valve within the system, the fluid products may then be transferred into one of the other bags, possibly for further processing.
Centrifugation of a biological fluid in typical biological fluid processing raises several issues. The high rotation speed allows stratification of the biological fluid (see FIG. 1B) but also induce strong shear on the cells. Some fluid products may also be affected by the high rotation speed. Furthermore, fractionation of a biological fluid, such as for example whole blood, by centrifugation lasts up to several hours and requires several manual steps and at least two centrifugations.
Systems based on filtration or centrifugation processes for separation of components in particle suspensions, notably but not limitatively cell suspensions such as biological fluid, whole blood, bone marrow, or cerebrospinal fluids, are well known in the art.
The present invention aims at overcoming the drawbacks of the prior art by providing a method for preparing all kinds of fluid products and an easy-to-use, closed, disposable, sterile, multiple fluid bag system enabling production of all the fluid products within a single system, limiting manual operations and also avoiding any centrifugation step.